Sci-Bytes : 2008 : 02.17.2008 - Hot Paper in Physics
SCI-BYTES - WHAT'S NEW IN RESEARCH
Week of February 17, 2008
Hot Paper in Physics
"Two-dimensional gas of massless Dirac fermions in
graphene," by K.S. Novoselov and 7 others, Nature,
438(7065): 197-200, 10 November 2005.
[Authors' affiliations: University of Manchester, U.K.; Institute for
Microelectronics, Chernogolovka, Russia; Radboud
University of Nijmegen, Netherlands]
Abstract: "Quantum electrodynamics (resulting from the
merger of quantum mechanics and relativity theory) has provided a clear
understanding of phenomena ranging from particle physics to cosmology and
from astrophysics to quantum chemistry. The ideas underlying quantum
electrodynamics also influence the theory of condensed matter, but quantum
relativistic effects are usually minute in the known experimental systems
that can be described accurately by the non-relativistic Schrodinger
equation. Here we report an experimental study of a condensed-matter system
(graphene, a single atomic layer of carbon) in which electron transport is
essentially governed by Dirac's (relativistic) equation. The charge
carriers in graphene mimic relativistic particles with zero rest mass and
have an effective 'speed of light' c* approximate to 10(6) m s(-1). Our
study reveals a variety of unusual phenomena that are characteristic of
two-dimensional Dirac fermions. In particular we have observed the
following: first, graphene's conductivity never falls below a minimum value
corresponding to the quantum unit of conductance, even when
concentrations of charge carriers tend to zero; second, the integer quantum
Hall effect in graphene
is anomalous in that it occurs at half-integer filling factors; and
third, the cyclotron mass m(c) of massless carriers in graphene is
described by E = m(c)c(*)(2). This two-dimensional system is not only
interesting in itself but also allows access to the subtle and rich
physics of quantum electrodynamics in a bench-top experiment."
This 2005 report from Nature was cited 102
times in current journal articles indexed by Thomson
Scientific during September-October 2007. Only one other physics paper
published in the last two years, aside from reviews, collected a higher
number of citations during that two-month period. Prior to the most recent
bimonthly count, citations to the paper have accrued as follows:
SOURCE:
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Sci-Bytes : 2008 : 02.17.2008 - Hot Paper in Physics